In floating aerator apparatus of the type referred to above, liquid from the body of liquid to be aerated is pumped up through a throat section or draft tube of the float unit by the power module, the latter generally including an electric motor which is powered from the shore through a connecting cable. The motor is often disposed upon a specially shaped, generally conical deflector or diffuser section which guides the movement of the liquid drawn up through the throat section by an impeller or propeller driven through a drive shaft driven by the motor, although this deflector design is dispensed with in other constructions. In all floating aerators of the type with which the invention is concerned, the power module must be mounted in spaced relationship to the float unit so as to permit the liquid drawn up through the throat section to be discharged between the power module and the float unit, the discharge generally taking place laterally around the periphery of the power module. To this end, a series of circumferentially disposed mounting bolts or studs are provided which serve to space the power module from the float unit and define open areas therebetween through which the discharge can take place.
It has been found that over the years the single most important cause of failure in surface aerators has to do with construction of the mounting or attachment arrangement for the power module described above. These constructions generally utilize shoulder bolts or what is known as single stud mounting arrangements. In the latter, four or more studs are screwed into the float unit and the power module is suspended above the float unit on these studs. The torque produced by the motor, which is particularly strong during starting or where heavy debris is being pumped through the throat, tends to turn the entire unit in a circle. However, because the float unit is relatively stationary, this turning force is resisted. Hence, the torque generated is transferred to the weakest point in the overall system and this point is the mounting studs. Because of this torque, the studs are eventually loosened and the power module is thus caused to lean far enough to one side that the propeller begins hitting the inner walls of the throat section of the float unit. At this point, some of the studs usually break and the power module falls to one side, in many cases causing the motor to burn out. The problem has been and continues to be a very costly one, with even the minimum expense for repairs being very substantial.
Although there are a number of different constructions and arrangements for mounting the power module of a floating aerator, all generally suffer the disadvantages discussed above and thus provide a weak link in the overall unit which ultimately results in damage to the aerator, with substantial attendant downtime and consequent expensive repairs. Some further examples of the mounting arrangements used in the prior art are those illustrated and described in U.S. Pat. Nos. 3,572,658 (Ravitts); 3,669,422 (Nogaj); 3,836,130 (Earhart et al); and 3,911,065 (Martin et al).